Root Nodule Formation on the Garden Bean, Studied by a Technique of Tissue Culture

Abstract

In 2 series of exps. involving approximately 350 root systems, it was shown that root-nodule bacteria (Rhizobium phaseoli) produce morphologically normal nodules (a) on excised roots (grown alone or in combination with etiolated whole plants or tops with adventitious roots), (b) on etiolated tops with adventitious roots only, and (c) on etiolated whole plants of a common variety of garden bean, Phaseolus vulgaris. Etiolated tissues were obtained from sterile seed and grown aseptically on a nutrient-salts agar containing also 0.5% sucrose. They were kept in complete darkness for 24-27 days. Such a technique of culture is of interest, since it offers a new approach to problems of infection and nodule development induced by Rhizobiums.